Photographic material utilizing an aromatic hydroxy compound and a 2-nitro-phenyl-aldehyde

ABSTRACT

Photo-sensitive material useful in wash-off imagery comprises a tannable hydrophilic colloid and a light-sensitive tanning agent precursor which is a mixture of an aromatic hydroxy compound and a 2&#39;&#39;-nitro-phenyl-aldehyde.

lliie iies elem 11 1 Levinos et a1.

[ Dec, 1111, 1974 [22] Filed:

Neithardt, Jr., Ridgefield, both of NJ.

[73] Assignee: Keuifel & Esser Company,

Morristown, NJ.

Aug. 20, 1973 [21] Appl'. No.: 390,149

[52] US. Cl 96/35, 96/33, 96/35.1,

96/115 P [51] lint. Cl G03c 1/68 [58] Field of Search 96/115 P, 35, 35.1, 33

[56] References Cited UNITED STATES PATENTS 3,368,900 2/1968 Burg 96/115 P Primary ExaminerDavid Klein Assistant Examiner--Alfonso T. Suro Pico Attorney, Agent, or Firm--Lionel N. White, Esq.

[5 7] ABSTRACT Photo-sensitive material useful in wash-off imagery comprises a tannable hydrophilic colloid and a lightsensitive tanning agent precursor which is a mixture of an aromatic hydroxy compound and a 2'-nitr0-phenylaldehyde.

9 Claims, N0 Drawings PIIQTOGRAPIIIC MATERIAL UTILIZING AN AROMATIC IIYDROXY COMPOUND AND A Z-NITRO-PHENYL-ALDEl-IYDE BACKGROUND The present invention relates to compositions useful in the so-called wash-off process of forming photographic images. For some time this general procedure has been utilized to prepare images by the exposure to a light pattern a material in which such exposure effects a change in the physical properties of the material, particularly a change in the solubility or susceptibility of the matter to swelling or tackifying when in contact with a developing fluid. Subsequent removal of the more soluble form of the matter from an exposed coated layer through the use of the developing fluid results in an image defining the original exposure pattern.

An early and widely-employed group of compositions useful in the wash off process were the bichromated colloids which tanned upon exposure to light substantially rich in'ultra-violet radiation. Thus, such natural colloids as glue, gelatin, and albumin, and synthetic hydrophilic polymers as polyvinyl alcohol and carboxymethyl cellulose were used to a great extent to prepar copies of line originals, engineering drawings, and the like. These materials suffered considerably, however, from a tendency to pretanning due to the bichromates included in the composition and thus exhibited unsatisfactory shelf life.

A group of wash-off imaging materials which have more recently found acceptance in the field are based for the most part on silver halide components which are dispersed in a substantially unhardened layer of tannable hydrophilic colloid. These materials utilize basic sil ver halide development chemistry in the formation of tanned colloid images in light-exposed areas; that is, the redox reaction resulting from the application of aromatic hydroxy developer compounds effects reduction to form a silver image and yields quinone-type oxidation products which tan the colloid at the development sites. Although these materials have been technologically successful, the growing scarcity of silver upon which these imaging compositions are wholly dependent presents a substantial limitation upon their continued employment.

SUMMARY The present invention provides a process for the for mation of images by means of the tanning of hydrophilic colloid materials and utilizes the quinone oxidation products of aromatic hydroxy compounds to effect such tanning. Unlike prior processes, however, this invention employs no precious metals such as silver, rather a light-sensitive 2'-nitro-phenyl-aldehyde is utilized in the imaging material. These aldehyde compounds, which apparently yield the corresponding nitro acids through photolysis, enter into a light-initiated redox reaction as a result of which aromatic hydroxy compounds present in the composition yield colloidtanning quinone oxidation products. The resulting decrease in the solubility of the colloid matrix of a coated composition at the light-exposed reaction sites thus renders the matter readily developable by a simple water wash removal of unexposed composition to yield replica of the imagewise light exposure.

DESCRIPTION The imaging materials of the present invention are generally in the form of a layer coated upon a suitable support such as paper, film, metal, glass, and the like. The layer of light-sensitive composition is prepared through the use of any of the commonly-employed pro cesses of which the photographic arts are wholly aware and which may be selected in accordance with the preferences of the practitioner.

The coatable composition of the present materials essentially comprises a matrix of a tannable hydrophilic colloid which serves as the binding medium of the composition and throughout which are distributed the aromatic hydroxy and light-sensitive 2'-nitro-phenylaldehyde tanning agent precursor compounds. These basic components may be readily formed into a fluid coating composition through the use of suitable solvent vehicles. Water preferably comprises a major proportion of such in view of the hydrophilic character of the colloid matrix. Additional water soluble or water compatible fluids or solvents of an organic nature may be included in the composition to assist in the solution or dispersion of the remaining components.

The tannable hydrophilic colloids employed in the compositions of the present invention include those natural and synthetic compounds which have previously been used in the general class of was'h-off materials. Such colloids are gelatin, casein, glue, starch, albumin, polyvinyl alcohol, saponified cellulose acetate, carboxymethyl cellulose, and the like.

While the greater proportion of the composition matrix generally comprises the tannable colloid, additional polymeric materials may be included to vary the physical properties according to the ultimate utilization of the material and the final image. Of particular advantage are various polymerizable components such as vinyl monomers and bifunctional cross-linking agents which have been found to increase the toughness and durability of tanned colloid imagesformed in the instant processes. For example, in the preparation of imaging material comprising, as the primary matrix component, gelatin upon which polymers may apparently be readily grafted, the incorporation of a vinyl monomer, such as acrylamide, and N-N'- methylenebisacrylamide as a cross-linking agent yields a composition which will provide particularly durable wash-off images after light exposure and development processing.

The aromatic hydroxy compound components of the tanning agent precursor utilized in the present invention may be selected from any of those compounds which are identified with the usual development of silver halide photographic materials. As with such prior utilization, these compounds may be employed singularly or in combination to effect the desired rate of tanning development depending upon the remaining components of the light-sensitive layers. Useful such compounds for this purpose include hydroquinone, chlorohydroquinone, catechol, pyrogalllol, 4-methoxy-1- naphthol, sodium salicylate, phloroglucinol, gallic acid, p-methylaminophenol, and the like. The amount of this component is a coated imaging composition may generally range from 5 to about 15 percent by weight.

The light-sensitive component of the tanning agent precursor combination may be one or more of the group of light-sensitive 2'mitro-phenyl-aldehydes such as o-nitro-benzaldehyde, 2,4-dinitrobenzaldehyde, 2,6- dinitrobenzaldehyde, o-nitrocinnamaldehyde. This component of the precursor combination may be employed in the ratio range of about 1 to 2 weight parts visual contrast of the image.

EXAMPLE 2 P P of the aromatic y y Compound present in In the manner dscribed in Example 1, imaging matea composition. rial was prepared from the following composition:

In accordance with the practices common in the fori Deionized water 240 ml. matron of wash-off images, the light-sensitive material l n (inert, high bloom) 20 gm. may be pre-dyed or pigmented to effect a desired de- Methanol 40 f b t th f I d th b Acetone 20 ml. gree o contrast e ween e ma image an e 0 Nitmbenzaldehyde 05 gm strate support. It should be recognized that the addition grllill rohlydroqilinone 0.4 gm. of such coloring matter to the composition interferes to some extent with the penetration of actinic radiation Exposure, wash development, and post-dyeing with through the composition and thereby extends the remethylene blue as in Example 1 yielded ,a durable conquired exposure times. Alternatively, a lightly-colored mm i composition devoid of contrasting pigments may be EXAMPLE 3 used in which event the resulting wash-off image can be visually intensified between application of dye solu- In the manner described Example gi g matetions or pigmented coloring matter which is specific to was Prepared from the following composltlon: the image or the substrate. Deionized water 240 Gelatin (inert, high bloom) 20 gm. Methanol 40 ml. Acetone 20 ml. PREFERRED EMBODIMENTS o-Nitrobenzaldehyde 0.4 gm. Pyrogallol 0.5 gm. The following examples embody a number of the 25. pMethylaminophenOl OJ gm photo-imag ng compositions of the present invention and md'cate general Exposure, wash development, and post dyeing with methylene blue as in Example 1 yielded a durable EXAMPLE 1 image of good contrast.

A solution of the following composition was pre- EXAMPLES 4-15 pared: In the manner generally described in Example 1,

com iti ns were re ared b substit in th es ec- Deionized water 60 ml. pos O p p y ut g e r Gelatin (high bloom, inert) 5 gm tive aldehyde and aromatic hydroxy compounds listed klethanol 2 below for the o-nitrobenzaldehyde and catechol there cetone m O Ni"obnza]dehyde 05 gm stated. Exposure, wash development, and post-dyeing Catechol 0.4 gm. as in Example 1 provided good images in all cases.

Example Aldehyde Aromatic Hydroxy 4 o-nitrobenzaldehyde 0.5 gm. chlorohydroquinone 0.4 gm. 5 o-nitrobenzaldehyde 0.5 gm. phloroglucinol 0.5 gm. 6 2,4-dinitrobenzaldehyde 0.6 gm. gallic acid 0.7 gm. 7 o-nitrocinnamaldehyde 0.6 gm. pyrogallol 0.6 gm. 8 o-nitrocinnamaldehyde 0.6 gm. gallic acid 0.7 gm. 9 onitrocinnamaldchyde 0.6 gmv phloroglucinol 0.6 gm. l0 o-nitrobenzaldehyde 0.45 gm. 4-methoxy-l-naphthol 0.5 gm. l l o-nitrobenzaldehyde 0.5 gm. sodium salicylate 0.5 gm. l2 o-nitrobenzaldehyde 1.0 gm. gallic acid 0.5 gm. l3 o-nitrobenzaldehyde 0.5 gm. hydroquinone 0.5 gm. [4 o-nitrobenzaldehyde 0.5 gm. pyrogallol 0.5 gm. l5 2.6-dinitrobenzaldehydc 0.6 gm. gallic acid 0.7 gm.

The gelatin was swelled and dissolved in the water, and the catechol was then dissolved in the solution. The aldehyde compound dissolved in a mixture of the methanol and acetone was then added to complete the coating composition. On a subbed polyester film support commonly employed in the preparation of the photographic materials, the mixture was applied to a wet thickness of about 75 micrometers and was air dried in the dark at room temperature. The coated side of the resulting imaging material was exposed through an opaque stencil for about three minutes to the light of a bank ofG.E. F8T5 BLB lamps, rich in ultra-violet radiation, separated by about 15 mm. and set at a distance of about 20 mm. from the imaging material. Subsequent to exposure, the coating was washed with water at about 3035C. to yield a relief image of hardened composition in the exposed areas. Application of As the artisans of the photographic field will recognize, the frontside exposure of wash-off materials is relegated to the formation of line and half-tone images, since adhesion of tanned image to base sheet is ensured by prolonged exposure. The materials of the present invention are nonetheless useful in continuous tone processing where they also enjoy the more rapid activity associated with that practice of exposing the imaging compositions through the substantially transparent base sheet. Exposure of material by this latter method can be employed to derive an indication of the relative photographic speed of wash-off compositions. Thus, it can be seen from the following examples that the present materials exhibit a significant rate of response which may yet be in effect improved by strengthening the resulting image through incorporation of polymerizable monomeric compositions.

EXAMPLE 16 Coated material was prepared according to the formulation of Example 5 and was imagewise exposed to the bank of lamps as in Example 1, but through the base sheet support, for a period of 30 seconds. Development treatment according to Example 1 resulted in a good relief image.

EXAMPLE 17 In the manner described in Example 1, a coating was prepared of the following composition:

Deionized Water 150 gm. Gelatin (inert, high bloom) 6.0 gm. Water 75.0 gm. Methanol 12.0 ml. Acetone 6.0 ml. Acrylamide 1.25 gm. N-N-methylenebisacrylamide 0.15 gm. o Nitrobenzaldehyde 0.6 gm. Phloroglucinol 0.3 gm.

A 20-second exposure and treatment of the resulting coating under the conditions otherwise described in Example 16 resulted in a similar durable image. The coated material likewise provided a good resist image when exposed in a conventional white-print machine at a speed of about 1.5 meters per minute.

What is claimed is:

1. Imaging material comprising a support and a coating thereon of a composition comprising:

a. a tannable hydrophilic colloid;

b. an aromatic hydroxy compound; and

c. a light-sensitive 2-nitro-phenyl-aldehyde.

2. Material according to claim 1 wherein said lightsensitive aldehyde was selected from the group consisting of o-nitrobenzaoldehyde, 2,4-dinitrobenzaldehyde, 2,6-dinitrobenzaldehyde,and o-nitrocinnamaldehyde.

3. Material according to claim 2 wherein said arosition comprises 55 to 90 parts by weight of said colloid, 5 to 15 parts by weight of said aromatic hydroxy compound, and 5 to 30 parts by weight of said lightsensitive aldehyde.

6. Material according to claim 5 wherein said colloid is gelatin.

7. A photo-imaging process comprising:

a. exposing material according to claim 1 imagewise to light for a time sufficient to effect tanning of said colloid in the light-exposed areas of said composition; and

b. effecting a visible distinction between the exposed, tanned and unexposed, untanned areas of said coating, thereby forming an image defining said imagewise light exposure.

8. The process according to claim 7 wherein said distinction is effected by removing unexposed areas of said composition from said support.

9. The process according to claim 8 wherein said removal is effected by washing the coated material with water.

a t r a: 

1. IMAGING MATERIAL COMPRISING A SUPPORT AND A COATING THEREON OF A COMPOSITION COMPRISING: A. A TANNABLE HYDROPHILIC COLLOID; B. AN AROMATIC HYDROXY COMPOUND; AND C. A LIGHT-SENSITIVE 2''-NITRO-PHENYL-ALDEHYDE.
 2. Material according to claim 1 wherein said light-sensitive aldehyde was selected from the group consisting of o-nitrobenzaoldehyde, 2,4-dinitrobenzaldehyde, 2,6-dinitrobenzaldehyde,and o-nitrocinnamaldehyde.
 3. Material according to claim 2 wherein said aromatic hydroxy compound is selected from a group consisting of hydroquinone, chlorohydroquinone, pyrogallol, catechol, phloroglucinol, p-methylaminophenol, gallic acid, sodium salicylate, and 4-methoxy-1-naphthol.
 4. Material according to claim 2 wherein said composition further comprises a polymerizable vinyl monomer.
 5. Material according to claim 1 wherein said composition comprises 55 to 90 parts by weight of said colloid, 5 to 15 parts by weight of said aromatic hydroxy compound, and 5 to 30 parts by weight of said light-sensitive aldehyde.
 6. Material according to claim 5 wherein said colloid is gelatin.
 7. A photo-imaging process comprising: a. exposing material according to claim 1 imagewise to light for a time sufficient to effect tanning of said colloid in the light-exposed areas of said composition; and b. effecting a visible distinction between the exposed, tanned and unexposed, untanned areas of said coating, thereby forming an image defining said imagewise light exposure.
 8. The process according to claim 7 wherein said distinction is effected by removing unexposed areas of said composition from said support.
 9. The process according to claim 8 wherein said removal is effected by washing the coated material with water. 